Shaker screen apparatus for mortar mixers

ABSTRACT

A PLASTER AND MORTAR MIXER INCLUDING A GENERALLY CYLINDRICALLY SHAPED MIXING DRUM HAVING A HORIZONTAL INLET OPENING IN THE TOP THEREOF ABOVE WHICH IS MOUNTED A SHAKER SCREEN FOR SCREENING THE PLASTER OR MORTAR PRIOR TO MIXING. THE SCREEN IS MOUNTED ON RUBBER SUPPORTS CARRIED BY THE MIXING DRUM AND IS MOVED IN A RECIPROCAL MANNER ABOVE THE INLET OPENING. THE RECIPROCAL MOTION IS PROVEDED BY FIRST AND SECOND ARMS WHICH ARE NORMALLY JOINED AND PIVOTALLY MOUNTED TO THE MIXING DRUM THE FIRST ARM HAVING MOTION INPARTED THERETO BY A CAM COAXIALLY MOUNTED   ON THE MIXING SHAFT AND THE SECOND ARM BEING CONNECTED TO THE SHAKER SCREEN.

May 23, 1972 o. L. WICKLUND 3,564,644

SHAKER SCREEN APPARATUS FOR MORTAR MIXERS Filed July 6, 1970 /a ZZ- Z2INVENTOR. 22 .DALE L. 'Mflcvmwvo MERCHHNT Gouw A 7' TORNEYS UnitedStates Patent 3,664,644 SHAKER SCREEN APPARATUS FOR MORTAR MIXERS DaleL. Wickluml, RR. 2, Box 157A, Deer River, Minn. 56636 Filed July 6,1970, Ser. No. 52,545

Int. Cl. B28c 5/14 US. Cl. 259-164 7 Claims ABSTRACT OF THE DISCLOSURE Aplaster and mortar mixer including a generally cylindrically shapedmixing drum having a horizontal inlet opening in the top thereof abovewhich is mounted a shaker screen for screening the plaster or mortarprior to mixing. The screen is mounted on rubber supports carried by themixing drum and is moved in a reciprocal manner above the inlet opening.The reciprocal motion is provided by first and second arms which arenormally joined and pivotally mounted to the mixing drum; the first armhaving motion imparted thereto by a cam coaxially mounted on the mixingshaft and the second arm being connected to the shaker screen.

BACKGROUND OF THE INVENTION The present invention relates to apparatusfor screening and mixing materials.

Prior to the utilization of certain materials (e.g. sand, cement,plaster, mortar, etc.), it is frequently necessary to screen thematerial to obtain a uniform size and to remove contaminants such asrocks, leaves and twigs. In large operations, such as in theconstruction of buildings, a screening plant is commonly utilized toscreen the materials prior to the use thereof. Such screening plantsare, of course, expensive to construct and operate and, consequently,are economically justifiable only when exceedingly large amounts ofmaterial are screened.

However, it is frequently necessary, or at least desirable, to screen asmaller quantity of material than that which is necessary to make theoperation of a screening plant practical. In such situations, it haspreviously been the practice to either 1) not screen at all, (2) screenby hand, or (3) allow the material to work its way through a stationarygrid mesh by force of gravity.

None of the above-mentional practices, however, have been particularlydesirable; practices (2) and (3) requir ing considerable timeand laborto obtain high quality screening. As a result, screening apparatus whichis (1) inexpensive to manufacture, and (2) provides efficient highquality screening is commercially desirable.

SUMMARY OF THE INVENTION The present invention provides asubstantiallyenclosed mixing chamber having a generally central axis and an openingtherein suitable for receiving a material to be mixed and fordischarging mixed material. A mixing shaft means is rotatably connectedto the mixing chamber extending generally coaxially therewith. Screeningmeans (e.g. a wire mesh screen) is positioned overlaying the opening inthe mixing chamber and is substantially coextensive therewith. Thescreen is moved in an agitating manner above the opening to facilitatescreening of the material deposited thereon. The agitating motion isprovided by reciprocal motion generating means connected to the mixingshaft means; and this reciprocal motion is then imparted to controlmeans which is connected to the screening means. In a preferredembodiment, the operative means comprises a cam and earn followeroperatively associated with the mixing shaft. The reciprocal motion isimparted to the screening means by the control means 3,664,644 PatentedMay 23, 1972 which includes first and second arms normally joined andpivotally connected to the mixing drum for converting the motionimparted thereto by the rotating cam and cam follower to a reciprocalmotion for agitating the material deposited on the screen.

The above-described apparatus has numerous advantages. First, itprovides an economical and efficient manner of screening materials suchas mortar, concrete, sand and the like. Secondly, the drive means (e.g.an electric motor) used to rotate the mixing shaft means is alsoutilized to impart the reciprocal motion to the material screen.Consequently, an additional motor is not required to operate thescreening mechanism. Thirdly, the screen can be mounted on the mixingdrum in such a manner so that it can be either removed or swung aside toallow easy cleaning of the drum.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings wherein likenumerals designate like parts of the invention throughout the figures:

FIG. 1 is a front elevational view of the present invention;

FIG. 2 is a top view of the embodiment shown in FIG. 1 illustrating aquantity of material carried by the screening apparatus of the presentinvention; and

FIG. 3 is a side elevational view of the embodiment shown in FIG. 1 morefully illustrating the apparatus for agitating the material carried bythe screen.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings,screening-mixer apparatus, generally designated 10, is shown ascomprising a mixing chamber or drum 12 having a horizontal opening 14therein in the top thereof above which is positioned a grid mesh orscreen 16. Mixing drum 12 has a generally cylindrical bottom andsubstantially vertical side walls extending upward therefrom to a hingedcover frame or frame 17. The hinged frame 17 has an opening thereinsubstantially coextensive with opening 14 for allowing material whichsifts through screen 16 to enter the mixing drum.

Screen 16 is mounted in a rectangularly shaped frame 18 which isgenerally coextensive with hinged frame 17. Flexible support means,shown as rubber mounts 19a, 19b, 19c and 19d, are fastened to the fourcorners of frame 18 and maintain it in a spaced relationship abovehinged frame 17. As will be more fully described hereinbelow, the rubbermounts allow screen 16 to be moved in a reciprocal manner above hingedframe 17 and inlet opening 14.

Mixing shaft means shown as a mixing shaft 20 and mixing paddles orblades 21 connected to shaft 20 provide mixing action within drum 12. Asillustrated, mixing drum 12 is carried by mixing shaft 20 which extendscoaxially with the central axis thereof. Shaft 20 extends exterior tomixing drum 12 and is supported by the vertical members 22a and 22b of aframe 22. The vertical members include conventional bearings 24a and 24b(e.g. sealed ball bearings) mounted therein so as to allow mixing shaft20 to be freely rotatable. Mixing drum 12 includes first and secondconventional bearings 25a and 25b, respectively, through which shaft 20rotatably extends so as to allow drum 12 to remain in an uprightposition when rotation of shaft 20 occurs. Mixing shaft 20 has a firstend thereof connected to a drive means, such as an electric motor (notshown) mounted within a housing 28. When actuated by a clutch mechanism(not shown) mounted within housing 28, the electric motor continuouslyrotates shaft 20 and blades 21 connected thereto.

An operative means comprising a cam 30 and a cam follower or roller 31is operatively associated with shaft 20 and a control means illustratedas first and second pivot arms 32 and 34, respectively. As illustrated,cam 30 is coaxially mounted on shaft 20 exterior to drum 12 and near theend of the shaft remote from the electric motor in housing 28. Roller 31is mounted on a first end of arm 1 32 in contact with cam 30 so as tomove along the lobes thereof upon rotation of the cam. Roller 31 is aconventional sealed roller bearing.

First pivot arm 32 has a first end pivotally connected to a conventionalpivoting means 38 (e.g. a hinge) which is rigidly mounted on mixing drum12 above shaft 20. Second pivot arm 34 includes a first end pivotallyconnected to a shaker arm 39 which extends substantially horizontallybetween its attachment to frame 18 and arm 34. A second end of pivot arm34 is normally joined to a second end of arm 32 and pivotally connectedto pivoting means 38. As illustrated, the first and second arms are aunitary structure pivotally connected at their normally joined ends tothe hinge 38-.

In operation, electric motor in housing 28 is actuated by a clutch lever40 when mixing is desired. Upon actuation, shaft 20 and blades 21connected thereto continuously rotate in a clockwise direction withrespect to FIG. 3 so as to provide a mixing action within the drum.Mixing drum 12, which is rotatably mounted on shaft 20, remains in theupright position illustrated in FIGS. 1-3 as a result of the clockwisemovement of shaft 20 and paddles 21 which causes engagement of a stopelement 41 with upright 22b and engagement of a latch bar 42 with stopelement 41. The material 50 which is to be mixed within drum 12 isplaced on horizontal screen 16 by any number of ways (e.g. byshoveling). As shaft 20 rotates, cam 30 is also caused to rotateimparting a reciprocal vertical movement to first arm 32 as roller 31moves along the lobes of rotating cam 20. The reciprocal vertical motionof arm 32 imparts a corresponding reciprocal movement to second arm 34causing the end of arm 34 connected to shaker arm 39 to reciprocallymove along a substantially horizontal are. This reciprocal movement ofsecond arm 34 is then imparted to screen 16 by the pivoted attachment ofshaker arm 39 to arm 34 thereby causing shaker arm 39 and frame 18 (inwhich screen 16 is secured) to move in a sifting or agitating manner asallowed by flexible supports 19a, 19b, 19c and 19d (i.e. a reciprocalhorizontal movement with respect to underlying frame 17) This reciprocalagitating motion of screen 16 causes a sifting of material 50 depositedon the screen; the sifted material falling through opening 14 into drum12 and being mixed therein by rotating blades 21.

When it is desired to empty mixer apparatus latch 42 is released andmixing drum 12 is rotated on shaft by manual force applied to handle 44so as to allow the mixed material to be exhausted from the mixingchamber through opening 14 and spout 46 by rotation of mixing paddles21. After the desired amount of mixed material has been exhausted, themixing drum is returned to its upright position wherein stop element 41engages upright 22b and is locked in position by latch bar 42; theamount of manual force which must be exerted on handle 44 to return drum12 to its upright position being reduced by the clockwise rotation ofpaddles 21.

When it is desirable to clean mixing chamber 12, shaker arm 39 isdisconnected from the frame 18. Frame 17 is then rotated on its hinges50a and 50!), along with screen 16 and frame 18, so that they no longercover inlet opening 14. With the screening apparatus in this position,mixing chamber 12 can be readily cleaned.

Whereas the present invention has been described in conjunction with onepreferred embodiment thereof, it will be readily apparent to those ofordinary skill in the art that changes can be made thereto withoutdeparting from the spirit and scope of the present invention.

What is claimed is:

1. Screening-mixer apparatus, comprising:

(a) a substantially enclosed mixing chamber having a generally centralaxis;

(b) a rotatably mounted, essentially horizontal mixing shaft extendinggenerally coaxially with said central axis of said mixing chamber andhaving a portion thereof extending horizontally exterior to said mixingchamber, said chamber being carried by said mixing shaft and mounted forrotation thereabout;

(0) means defining a substantially horizontal opening positioned in saidmixing chamber above said mixing shaft for introducing material intosaid chamber and for discharging said material therefrom;

(d) screening means positioned horizontally above said opening andgenerally coextensive therewith;

(e) means attached to said mixing shaft and rotatable therewith formixing material introduced into said mixing chamber;

(f) means for generating reciprocal motion including a cam mounted onsaid mixing shaft exterior to said mixing chamber and a cam followeroperatively associated with said cam; and

(g) control means connecting including first and second rigidlyconnected cams pivotally mounted on said mixing chamber and having oneof said first and second arms connected to said screening means and saidcam follower rotatably connected to the other of said first and secondarms for imparting an agitating motion to said screening means.

2. The screening-mixer apparatus of claim 1 wherein:

(a) said cam follower is rotatably connected to said first arm; and

(b) said second arm means is connected to said screening means andimparts said agitating motion thereto.

3. The screening-mixer apparatus of claim 1 wherein:

(a) said opening is substantially rectangular;

(b) said screening means includes a rectangular screen frame generallycoextensive with said inlet opening and a screen rigidly held by saidframe;

(0) said agitating motion of said screen frame and screen is areciprocal motion along a direction substantially parallel to saidmixing shaft.

4. The screening-mixer apparatus of claim 3 wherein:

(a) said first arm is substantially horizontal and includes first andsecond ends;

(b) said cam follower is rotatably mounted on said first end of saidfirst arm; and

(c) said second arm is substantially vertical and includes first andsecond ends, said screen frame being pivotally connected to said firstend of said second arm and said second end being rigidly connected tosaid second end of said first arm.

5. The screening-mixer of claim 4 including flexible support means and acover frame for said mixing chamber wherein:

(a) said flexible support means are connected to said screen frame andextend downward to said cover frame for maintaining a space relationshiptherebetween and for allowing said agitating motion thereof; and

(b) said cover frame is pivotally connected to said mixin chamber andincludes an opening therein substantially coextensive with said openingin said mixing chamber.

6. Screening-mixer apparatus, comprising:

(a) a mixing chamber having a generally horizontal central axis and anopening therein suitable for introducing a material into said chamberand discharging said material therefrom;

(b) mixing shaft means rotatably connected to said mixing chamber andextending coaxially therewith, said mixing shaft means being adapted forconnection to means for imparting rotation thereto;

(c) cam means connected to said mixing shaft means and rotatabletherewith for generating a reciprocal motion;

((1) screening means overlaying said inlet opening substantiallycoextensive therewith and mounted for reciprocal motion thereabove; and

(e) arm means connecting said cam means and said screening means forimparting said reciprocal motion to said screening means upon rotationof said cam means.

7. The screening-mixer of claim 6 including frame means wherein:

(a) said mixing shaft means is rotatably supported by said frame meansso as to allow rotation of said mixing shaft means;

(b) said arm means includes first and second arms pivotally connected tosaid mixing chamber; and (0) said cam means includes a cam rigidlyconnected to said shaft means and a cam follower rotatably mounted onone of said first and second arms positioned to rotate with said camupon rotation thereof.

References Cited UNITED STATES PATENTS PETER FELDMAN, Primary ExaminerUS. Cl. X.R.

